Electrolytic Composition for Degrading Polymeric Filter Cake

ABSTRACT

An aqueous breaking fluid having an aqueous fluid, powder particles, and at least one reducing sugar may be helpful in degrading a polymeric filter cake downhole. The aqueous breaking fluid may be introduced through a wellbore. The aqueous fluid may be or include water, brine, acid, alcohol, a mutual solvent, and mixtures thereof. A coating material of each metallic powder particle may be disintegrated such that the particle core may be released from the powder particle. The aqueous breaking fluid, which may include the reducing sugar and the released particle core, may contact and degrade the polymeric filter cake.

CROSS-REFERENCES TO RELATED APPLICATION

This application claims the benefit of Provisional Patent Application No. 61/521,649 filed Aug. 9, 2011, which is incorporated by reference herein in its entirety.

TECHNICAL FIELD

The present invention relates to a method for degrading a downhole polymeric filter cake by introducing an aqueous breaking fluid that may include an aqueous fluid, at least one reducing sugar, and metallic powder particles as a co-breaking agent that may be controllably and selectably disintegrated to contact and degrade the polymeric filter cake with the reducing sugars.

BACKGROUND

Polymeric filter cakes are a byproduct of typical well operations, such as hydraulic fracturing and subsequent drill operations. Removal of polymeric filter cakes have proven to be problematic, even though various methods of removal are currently used, such as the application of acids, strong oxidative solutions, or enzymatic processes. However, these methods do not allow for the timing and/or conditions of the filter cake degradation to occur in a controlled manner.

Drilling operations require the use of drilling fluids, drill-in fluids, completion fluids, and stimulation fluids. These fluids typically have natural polymers as additives to allow the fluid to have better friction reductions, viscosification, particle transport, fluid loss control, and/or zonal isolation depending on the fluid. These polymers are incidentally deposited as a filter cake on the wellbore wall. The presence of a filter cake may block flow, dramatically reducing the productivity of the well.

Filter cakes are the residue deposited on a permeable medium, such as a formation surface when a slurry or suspension, such as a drilling fluid, is forced against the medium under pressure. Filtrate is the liquid that passes through the medium, leaving the filter cake on the medium. Cake properties such as cake thickness, toughness, slickness and permeability are important because the cake that forms on permeable zones in a wellbore may cause stuck pipe and other drilling or production problems. Reduced hydrocarbon production may result from reservoir or skin damage when a poor filter cake allows deep filtrate invasion. In some cases, a certain degree of cake buildup is desirable to isolate formations from drilling fluids. In open hole completions in high-angle or horizontal holes, the formation of an external filter cake is preferable to a cake that forms partly inside the formation (internal). The latter has a higher potential for formation damage.

It will be appreciated that in the context of this invention the term “polymeric filter cake” includes any polymeric portion of a filter cake, and that the filter cake is defined as a combination of any added solids, if any, such as proppant and drilled solids. It will also be understood that the filter cake is concentrated at the bore hole face and/or hydraulic fracture face created inside the formation.

Further, it is often desirable in the destruction and removal of polymeric filter cake to not do so quickly, but rather to delay the destruction and removal of the filter cake. Without control of the destruction rate, massive brine losses may occur quickly and/or before the work string can be safely pulled out of the open wellbore.

It would be desirable if methods could be devised to aid and improve the ability to clean up filter cake, and to remove it more completely, without causing additional formation damage. It is also desirable to delay the rate of destruction and removal of the polymeric filter cake so that the timing of its removal is controlled.

SUMMARY

There is provided, in one form, a method for degrading a polymeric filter cake downhole. An aqueous breaking fluid may be introduced through a wellbore that may include an aqueous fluid, metallic powder particles, and at least one reducing sugar. The aqueous fluid may be or include water, brine, acid, alcohol, mutual solvent, and mixtures thereof. Each metallic powder particle may have a coating material and a particle core. The coating material may be disintegrated such that the particle core is released from the metallic powder particle. The action of the reducing sugar and the metal ions released from the coating material and/or the particle core may contact and degrade the polymeric filter cake. The release of the metal ions into the aqueous medium is controlled by a particular rate of dissolution for the coating material. The coating material may have one dissolution rate and the particle core may have a different dissolution rate from that of the coating material.

In one non-limiting embodiment, both the coating material and the particle core within the metallic powder particle may include one or more metals, such as but not limited to an elemental metal, a chelated metal, a metal complex, a metal oxide or hydroxide, a metal alloy, and combinations thereof. The aqueous breaking fluid may also include a surfactant.

In another non-limiting example, a method may include degrading a polymeric filter cake by introducing an emulsion breaking fluid through the wellbore. The emulsion breaking fluid may include an aqueous continuous phase, a non-aqueous dispersed phase, and at least one surfactant. The aqueous continuous phase may include at least one reducing sugar. The non-aqueous dispersed phase may include metallic powder particles where the metallic powder particle may have a coating material and a particle core. The method may include breaking the emulsion of the emulsion breaking fluid for release of the metallic powder particles. The coating material of each released powder particle may be disintegrated for release of the particle core. The emulsion breaking fluid, which may include the reducing sugar and the metal ions released by dissolution of the coating material and/or the particle core, may contact the polymeric filter cake. The action of the reducing sugar and the released metal ions may degrade the polymeric filter cake

The powder particles appear to enhance the controllability of the dissolution rate, the timing, and/or the conditions of the filter cake degradation.

DETAILED DESCRIPTION

It has been discovered that the addition of powder particles as a co-breaking agent to an aqueous breaking fluid may allow for better control of the degradation of a polymeric filter cake. The selectable and controllable disintegration characteristics of the metallic powder particles also allow the dimensional stability and strength of the metallic powder particles to be maintained until the coating material and/or the particle cores are needed, at which time a predetermined condition may be changed to promote the disintegration of the coating material of the powder particles. The predetermined condition may include, but is not necessarily limited to a wellbore condition, including but not necessarily limited to wellbore fluid temperature, downhole pressure, fluid pH value, salt or brine composition.

The disintegration of the coating material and subsequent release of the particle core, and thereby the degradation of the filter cake, may be postponed until the aqueous breaking fluid is properly positioned to allow for better activity and better contact with the filter cake. Moreover, the combination of components within the aqueous breaking fluid (i.e. the powder particles, the reducing sugar, and the aqueous fluid) is much more effective for degrading a polymeric filter cake than these components used alone. The metal ions, such as but not limited to the transition metals, released from the degradable coating material and/or the particle core of each metallic powder particle may catalyze the breaking activity of the reducing sugars. In one non-limiting embodiment, these disintegrative metals may be called controlled electrolytic metallics or CEM.

These coated powder particles may include various electrochemically-active (e.g. having relatively higher standard oxidation potentials), lightweight, high-strength particle core materials, such as electrochemically active metals. While it is desirable for the coating material of each metallic powder particle to disintegrate, as a practical matter in an alternate embodiment, it may not be possible to contact and disintegrate all coating materials of all powder particles. The disintegration of the coating material may occur by a method, such as but not limited to dissolving the coating material, degrading the coating material, corroding the coating material, melting the coating material, and combinations thereof.

Methods for using these coated powder particles are described in further detail below, as well as in U.S. patent application Ser. No. 12/633,686 entitled COATED METALLIC POWDER AND METHOD OF MAKING THE SAME, filed Dec. 8, 2009, which is herein incorporated by reference in its entirety.

When the aqueous breaking fluid is introduced through a wellbore, the coating material of the powder particles may be disintegrated at a later time for release of the particle core of each powder particle. Upon disintegration, the metal portion of the coating material and/or the particle core that is released from the metallic powder particles catalyzes the breakdown of the reducing sugar, which aids in the degradation of the filter cake. The metallic powder particles are added to the aqueous breaking fluid in an amount effective to catalyze the reducing sugars for breaking down the sugar molecule directly. The metal ion may be employed on a catalyst substrate. The sequence of addition of the reducing sugar and the metal ion is not critical to the reaction or the reaction rate. The metallic powder particles may be added to the aqueous breaking fluid at the same time as the reducing sugars, before the reducing sugars, or after the reducing sugars, etc. Typical or expected polymeric filter cake materials that may be degraded by these methods may include, but are not limited to, xanthan, guar, cellulose, starches, derivatives thereof, and the like.

Without being limited to any one theory, it is thought that increasing amounts of metal ion present, in conjunction with the reducing sugars, accelerates the breaking activity of the polymers within the filter cake and would thus accelerate the filter cake degradation. The divalent iron ion(s) may act as one of the better catalyzing agents for the methods described, and thereby provide some of the most rapid filter cake degradation when so desired. However, the use of metal ions from the coating materials and/or the particle cores together with the reducing sugars may break the polymers of the filter cake even faster than when the reducing sugars are used alone to indicate a catalytic mechanism, and/or at least a synergistic effect. The catalytic mechanism with regards to the types of metals and metal ions and the reducing sugars is discussed at length in U.S. Pat. No. 7,084,093 entitled CATALYZED POLYOL GEL BREAKER COMPOSITIONS, filed Jul. 25, 2003, which is herein incorporated by reference in its entirety.

Complete degradation of the polymeric filter cake is desirable, but it should be appreciated that complete degradation is not necessary for the methods discussed herein to be considered effective. Success is obtained if more polymeric filter cake material is removed using the aqueous breaking fluid than in the absence of the aqueous breaking fluid. Alternatively, the methods described are considered successful if a majority of the polymeric filter cake material is removed.

The disintegratable powder particles may be spherical, elongated, rod-like or another geometric shape. The particle core of the powder particles may include, but is not limited to at least one metal or metal alloy selected from the Periodic Table Groups VIB, VIIB, VIII, IB, IIB, alloys thereof and combinations thereof. The particle core may be, but is not limited to, an elemental metal, a chelated metal, a metal complex, a metal oxide, a metal hydroxide, a metal alloy, and combinations thereof. Additional examples of these types of metals may include but are not limited to molybdenum, manganese, iron, cobalt, copper, zinc, chromium, nickel, palladium, alloys thereof and combinations thereof. These metals may be used as pure metals or in any combination with one another, including various alloy combinations of these materials, including binary, tertiary, or quaternary alloys of these materials.

Nanoscale metallic and/or non-metallic coating materials may be applied to these electrochemically active metallic particle cores to further strengthen the material and to provide a means to accelerate or decelerate the disintegrating rate of the coating material. The coating material may be, but is not limited to, an elemental metal, a chelated metal, a metal complex, a metal oxide, a metal hydroxide, a metal alloy, and combinations thereof. The coating material may be formed by any acceptable method known in the art and suitable methods include, but are not necessarily limited to, chemical vapor deposition (CVD) including fluidized bed chemical vapor deposition (FBCVD), as well as physical vapor deposition, laser-induced deposition and the like.

A plurality of these metallic powder particles are not sintered and/or further compacted together; these powder particles are in powder-form. In an alternative embodiment, the coated powder particles are sintered and further compacted together. In another non-limiting version, the metallic powder particle may be formed of two approximately equal, or even unequal, hemispheres, one of which is a relatively insoluble portion and the other of which is a relative dissolvable portion.

One version of an alternate embodiment of a coating material may have at least two coating layers therein. A first coating layer may be disintegrative at one rate, and a second coating layer may be disintegrative at a second rate. In another non-limiting embodiment, the first coating layer may be more slowly disintegrative compared to the second coating layer, which may be relatively more rapidly disintegrative. It should be understood that the rates of disintegration between the first coating layer and the second coating layer may be reversed.

The first coating layer may be uniformly disposed on the generally central particle core of each metallic powder particle. However, it will be appreciated that the powder particles may have other configurations, for example the coating material may not be uniformly applied over the particle core. The second coating layer may be uniformly disposed on the first coating layer. ‘First coating layer’ and ‘second coating layer’ as used herein are defined in relation to the generally central particle core, i.e. the ‘first coating layer’ is closest to the particle core, the ‘second coating layer’ may be disposed on the ‘first coating layer’, a ‘third coating layer’ may be disposed on the second coating layer and so forth.

The first coating layer may include a metal, such as but not limited to Al, Zn, Zr, Mn, Mg, Mo, W, Cu, Fe, Si, Ca, Co, Ta, Ti, Re, Ni, an oxide thereof, a hydroxide thereof, a carbide thereof, a nitride thereof, an alloy thereof, and a combination of any of the aforementioned materials. The second coating layer and any additional coating layers may include a metal, such as but not limited to Al, Zn, Zr, Mn, Mg, Mo, W, Cu, Fe, Si, Ca, Co, Ta, Ti, Re, Ni, an oxide thereof, a hydroxide thereof, a carbide thereof, a nitride thereof, an alloy thereof, and a combination of any of the aforementioned materials. The first coating layer may have a chemical composition that is different from the second coating layer, which may have a chemical composition that is different from any additional coating layer.

In one non-restrictive version, the average particle size of a metallic powder particle may range from about 4 nm to about 100 μm, or alternatively from about 6 nm to about 20 μm. The total disintegrative coating material (even if the coating material has more than one coating layer) may range from about 0.5 nm independently to about 1000 nm thick, alternatively from about 2 nm independently to about 200 nm thick. The size of the particle core of each metallic powder particle may range from about 4 nm to about 100 μm, or from about 6 nm to about 20 μm in another non-limiting embodiment.

There are at least three different temperatures involved: T_(P) for the particle core, T_(C) for the coating material, and a third one T_(PC) for the binary phase of P and C. T_(PC) is normally the lowest temperature among the three. In a non-limiting example, for a Mg particle with an Al coating material, according to a Mg—Al phase diagram, T_(P)=650° C., T_(C)=660° C. and T_(CP)=437 to <650° C. depending on wt % ratio of the Mg—Al system. The metallic powder particles may be configured for solid-state sintering to one another to form a metallic particle compact at a predetermined sintering temperature (T_(s)) that is less than T_(p) and T_(c).

Disintegrative enhancement additives to the metallic powder particle may include, but are not necessarily limited to, magnesium, aluminum, nickel, iron, cobalt, copper, tungsten, rare earth elements, and alloys thereof and combinations thereof. It will be observed that some elements are common to both lists, that is, those metals which can form a disintegrative coating material and/or a particle core versus those which can enhance such disintegrative coating materials and particle cores. The function of the metals, alloys or combinations depends upon what metal or alloy is selected as the major composition or particle core first.

The relative disintegrative rate depends on the value of the standard potential of the additive or disintegrative coating material relative to that of the particle core. For instance, to make a relatively more slowly disintegrating coating material, the composition of the additive or disintegrating coating material needs to have lower standard potential than that of the particle core. An Mg particle core with a Fe—Al—Ni disintegrative coating material is a suitable example. Or, to make this disintegrative coating material dissolve faster, standard potential of the disintegrative coating material needs to be lower than that of the particle core. An example of this latter situation would be a Al particle core with a Fe—Ni disintegrative coating material.

In an alternative embodiment, the powder particles may be within a non-aqueous dispersed phase, such as but not limited to mineral oils, plant oils, plant solvents, synthetic oils, and mixtures or combinations thereof. In one non-limiting embodiment, the amount of the powder particles within the aqueous breaking fluid may range from about 0.01 ppm independently to about 10,000 ppm, or from about 1 ppm independently to about 1000 ppm in another non-limiting embodiment. As used herein with respect to a range, “independently” means that any lower threshold may be used together with any upper threshold to give a suitable alternative range.

The aqueous breaking fluid may also include an aqueous fluid and at least one reducing sugar. A ‘reducing sugar’ as used herein is a type of sugar or sugar alcohol that acts as a reducing agent. The reducing sugar may be or include, but is not limited to mannitol, sorbitol, xylitol, glycerol, glucose, fructose, maltose, lactose, tagatose, psicose, galactose, xylose, allose, ribose, arabinose, rhanmose, mannose, altrose, ribopyranose, arabinopyranose, glucopyranose, gulopyranose, galatopyranose, psicopyranose, allofuranose, gulofuranose, galatofuranose, glucosamine, chondrosamine, galactosamine, ethylhexo glucoside, methyl-hexo glucoside, aldaric acid, sodium aldarate, glucaric acid, sodium glucarate, gluconic acid, sodium gluconate, glucoheptonic acid, sodium glucoheptonate, and mixtures thereof.

The amount of the reducing sugar may be added to the aqueous breaking fluid in an amount ranging from about 0.1 pptg independently to about 120 pptg based on the total volume of the aqueous breaking fluid, or from about 0.5 pptg independently to about 50 pptg in an alternative embodiment.

It will be appreciated that derivatives of these relatively simple reducing sugars will also find use in the inventive methods. Suitable derivatives include, but are not necessarily limited to, acid, acid salt, alcohol, alkyl, and amine derivatives of these saccharides, and mixtures of reducing sugars and/or the derivatives thereof. Specific examples of suitable derivatives include, but are not necessarily limited to, alkyl glucosides, alkyl polyglucosides, alkyl glucosamides, alkyl glucosamines, alkyl sorbitans, alkyl sorbitols, alkyl glucopyranosides, alkyl maltosides, alkyl glycerols and mixtures thereof. The alkyl groups of these derivatives may be C₂ to C₃₆ straight, branched, or cyclic alkyls.

The aqueous fluid may include, but is not limited to water, brine, acid, alcohol, mutual solvent, and mixtures thereof. In another non-limiting example, the aqueous breaking fluid may include at least one surfactant, such as but not limited to non-ionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and combinations thereof. The amount of the surfactant within the aqueous breaking fluid may range from about 0.1 gptg independently to about 80 gptg, or from about 0.5 gptg to about 5 gptg in an alternative embodiment.

Suitable nonionic surfactants include, but are not necessarily limited to, alkyl polyglycosides, sorbitan esters, methyl glucoside esters, amine ethoxylates, diamines ethoxylates, polyglycerol esters, alkyl ethoxylates, polypropoxylated and/or ethoxylated alcohols, sorbitan fatty acid esters including phospholipids, alkyl polyglycosides, gemini surfactants, sorbitan monooleate, sorbitan trioleate, glycerol fatty acid esters including mono- and/or dioleates, polyglycols, alkanolamines and alkanolamides such as ethoxylated amines, ethoxylated amides, ethoxylated alkanolamides, including non-ethoxylated ethanolamides and diethanolamides, and the like as well as block copolymers, terpolymers and the like.

Suitable cationic surfactants include, but are not necessarily limited to, arginine methyl esters, alkyl amines, alkyl amine oxides, alkanolamines and alkylenediamides. In one non-limiting embodiment the suitable anionic surfactants include alkali metal alkyl sulfates, alkyl ether sulfonates, alkyl sulfonate, branched ether sulfonates, alkyl disulfonate, alkyl disulfate, alkyl sulfosuccinate, alkyl ether sulfate, branched ether sulfates. Amphoteric or zwitterionic surfactants include, but are not necessarily limited to alkyl betaines and sulfobetaines.

In an alternative embodiment, the aqueous breaking fluid may include additional additives, such as but not necessarily limited to co-surfactants, viscosifiers, filtration control additives, suspending agents, dispersants, wetting agents, and mixtures thereof.

The aqueous breaking fluid may be introduced through the wellbore by pumping the aqueous breaking fluid downhole. In order to practice the method of the invention, the aqueous breaking fluid is first prepared by mixing the plurality of compacted masses and the reducing sugar into an aqueous fluid. Any suitable mixing apparatus may be used for this procedure. In the case of batch mixing, the components of the aqueous breaking fluid may be blended for a period of time sufficient to suspend or disperse the compacted masses within the aqueous breaking fluid.

After the aqueous breaking fluid has been positioned at or near the polymeric filter cake, a subsequent dosing of a second fluid in an alternate embodiment, different from the aqueous breaking fluid may be used to trigger the disintegration of the coating material. This second fluid may suitably be, but is not necessarily limited to, fresh water, brines, acids, hydrocarbons, emulsions, and combinations thereof so long as it is designed to dissolve all or at least a portion of the dissolvable particles. The acid may be a mineral acid (where examples include, but are not necessarily limited to HCl, H₂SO₄, H₂PO₄, HF, and the like), and/or an organic acid (where examples include, but are not necessarily limited to acetic acid, formic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, citric acid, and the like). The second fluid may contain corrosive material, such as select types and amounts of acids and salts, to control the rate of disintegration of the coating material. ‘Second fluid’ as used herein is defined as being any fluid used in conjunction with the aqueous breaking fluid capable of disintegrating the coating material of the powder particles. The ‘second fluid’ does not necessarily have to be pumped through the wellbore after the aqueous breaking fluid.

In a non-limiting embodiment, the aqueous breaking fluid may be introduced into the wellbore by means of an emulsion, which would sustain the aqueous breaking fluid when subjected to high temperatures, such as but not limited to 250 F or higher. In another embodiment, the emulsion may be, but is not limited to a microemulsion, a macroemulsion, a miniemulsion, a nanoemulsion, and combinations thereof. Microemulsions are thermodynamically stable, macroscopically homogeneous mixtures of at least three components: an aqueous phase, a non-aqueous phase, and a surfactant. Microemulsions may form spontaneously and differ markedly from the thermodynamically unstable macroemulsions, which depend upon intense mixing energy for their formation. The macroemulsion also has a larger particle size than the microemulsion. Generally, the particle or internal phase droplet size for miniemulsions is between that of macroemulsions and microemulsions, whereas the droplet or particle size of the internal phase for nanoemulsions is on the order of a nanometer or smaller.

The surfactant may form a monolayer at the interface of the aqueous phase and the non-aqueous phase, with the hydrophobic tails of the surfactant molecules dissolved in the non-aqueous phase and the hydrophilic head groups in the aqueous phase.

The aqueous phase may be or include but is not limited to a water-based fluid and at least one reducing sugar. The non-aqueous phase may be or include, but is not limited to an oil-based fluid and powder particles. All components of the emulsion may be components similar to those described previously, such as the metals and metal alloys, the reducing sugars, and/or the surfactants depending on the desired result for the emulsion breaking fluid. It will be appreciated that the amount of emulsion-forming components (an aqueous phase, a non-aqueous phase, and a surfactant) to be used is difficult to determine and predict with much accuracy since it is dependent upon a number of interrelated factors including, but not necessarily limited to, the aqueous phase fluid, the reducing sugar, the powder particles, the specific filter cake material, the temperature of the formation, the particular surfactant or surfactant blend used, whether a chelating agent is present and what type, etc.

Nevertheless, in order to give some idea of the quantities used, in one non-limiting embodiment, the proportion of non-brine components in the emulsion may range from about 2 vol % independently to about 60 vol %, from about 5 vol % independently to about 40 vol %, and in another non-limiting embodiment may range from about 10 vol % independently to about 30 vol %. Alternatively, the ranges and amounts of the types of reducing sugars and/or the types of powder particles within the aqueous breaking fluid, previously mentioned, may be applicable to the emulsion as well. Water-based fluids, such as brines in a non-limiting embodiment, may be a desired component for the aqueous phase of the emulsion breaking fluid. Any of the commonly used brines, and salts to make them, are expected to be suitable in the compositions and methods of this invention.

In the foregoing specification, the invention has been described with reference to specific embodiments thereof, and has been described as effective in providing methods and compositions for degrading a polymeric filter cake downhole. However, it will be evident that various modifications and changes can be made thereto without departing from the broader spirit or scope of the invention as set forth in the appended claims. Accordingly, the specification is to be regarded in an illustrative rather than a restrictive sense. For example, specific aqueous fluids, metal or metallic alloy powder particles, disintegrative coating materials, and reducing sugars falling within the claimed parameters, but not specifically identified or tried in a particular composition or method, are expected to be within the scope of this invention.

The present invention may suitably comprise, consist or consist essentially of the elements disclosed and may be practiced in the absence of an element not disclosed. For instance, the method may consist of or consist essentially of a method for degrading a polymeric filter cake downhole by introducing an aqueous breaking fluid consisting of or consisting essentially of an aqueous fluid, at least one reducing sugar, and powder particles having a particle core and a coating material, which may be disintegrated to release the particle core and aid in degradation of the polymeric filter cake.

The words “comprising” and “comprises” as used throughout the claims, are to be interpreted to mean “including but not limited to” and “includes but not limited to”, respectively. 

1. A method for degrading a polymeric filter cake downhole, the method comprising: introducing an aqueous breaking fluid through a wellbore, where the aqueous breaking fluid comprises: an aqueous fluid selected from the group consisting of water, brine, an acid, an alcohol, a mutual solvent, and mixtures thereof; metallic powder particles, wherein each metallic powder particle comprises: a particle core having a melting temperature (T_(p)); and a coating material disposed on the particle core, wherein the coating material has a melting temperature (T_(c)); and at least one reducing sugar; and disintegrating the coating material to release the particle core; and contacting the polymeric filter cake with at least the released particle core and the at least one reducing sugar for degrading the polymeric filter.
 2. The method of claim 1, wherein the metallic powder particles are configured for solid-state sintering to one another to form a metallic particle compact at a predetermined sintering temperature (T_(s)), wherein T_(s) is less than T_(p) and T_(c).
 3. The method of claim 1, wherein the particle core comprises a metal selected from the Periodic Table Groups VIB, VIIB, VIII, IB, IIB, alloys thereof, and combinations thereof.
 4. The method of claim 1, wherein the particle core comprises a metal selected from the group consisting of an elemental metal, a chelated metal, a metal complex, a metal oxide, a metal hydroxide, a metal alloy, and combinations thereof.
 5. The method of claim 1, wherein the coating material comprises a metal selected from the group consisting of an elemental metal, a chelated metal, a metal complex, a metal oxide, a metal hydroxide, a metal alloy, and combinations thereof; and wherein the coating material has a chemical composition that is different from the chemical composition of the particle core.
 6. The method of claim 1, wherein the size of the particle core ranges from about 4 nm to about 100 μm, and wherein the thickness of the coating material ranges from about 0.5 nm to about 1000 μm.
 7. The method of claim 1, wherein the coating material comprises a single coating layer.
 8. The method of claim 1, wherein the coating material comprises a plurality of coating layers, wherein the plurality of coating layers comprises a first coating layer disposed on the particle core and at least a second coating layer disposed on the first coating layer.
 9. The method of claim 8, wherein the first coating layer comprises a metal selected from the group consisting of Al, Zn, Zr, Mn, Mg, Mo, W, Cu, Fe, Si, Ca, Co, Ta, Ti, Re, Ni, an oxide thereof, a hydroxide thereof, a carbide thereof, a nitride thereof, an alloy thereof, and a combination of any of the aforementioned materials; wherein the at least second coating layer comprises a metal selected from the group consisting Al, Zn, Zr, Mn, Mg, Mo, W, Cu, Fe, Si, Ca, Co, Ta, Ti, Re, Ni, an oxide thereof, a hydroxide thereof, a carbide thereof, a nitride thereof, an alloy thereof, and a combination of any of the aforementioned materials; and wherein the first coating layer comprises a chemical composition that is different from the at least second coating layer.
 10. The method of claim 1, wherein amount of the metallic powder particles in the aqueous breaking fluid ranges from about 0.01 ppm to about 10,000 ppm.
 11. The method of claim 1, wherein the disintegration of the coating material occurs by a method selected from the group consisting of a temperature change; the presence of an acid, a salt, a pH buffer; an amount of time; and combinations thereof.
 12. The method of claim 1, wherein the metallic powder particles are within a non-aqueous dispersed phase of the aqueous breaking fluid.
 13. The method of claim 1, wherein the aqueous breaking fluid is an emulsion having at least three components, wherein the at least three components comprise an aqueous continuous phase, a non-aqueous dispersed phase, and at least one surfactant, and wherein the metallic powder particles are within the non-aqueous dispersed phase.
 14. The method of claim 1, further comprising reducing the permeability and/or size of the filter cake as compared to contacting the filter cake with an aqueous breaking fluid absent the metallic powder particles.
 15. The method of claim 1, wherein the size of the metallic powder particles ranges from about 4 nm to about 100 μm.
 16. A method for degrading a polymeric filter cake downhole, the method comprising: introducing an emulsion breaking fluid through a wellbore, where the emulsion breaking fluid comprises: an aqueous continuous phase comprising at least one reducing sugar; and a non-aqueous dispersed phase comprising metallic powder particles, wherein each metallic powder particle comprises: a particle core having a melting temperature (T_(p)); and a coating material disposed on the particle core, wherein the coating material has a melting temperature (T_(c)); and at least one surfactant; breaking the emulsion of the emulsion breaking fluid for release of the metallic powder particles; disintegrating the coating material to release the particle core; and contacting the polymeric filter cake with at least the released particle core and the at least one reducing sugar for degrading the polymeric filter cake.
 17. The method of claim 16, wherein the metallic powder particles are configured for solid-state sintering to one another to form a metallic particle compact at a predetermined sintering temperature (T_(s)), wherein T_(s) is less than T_(p) and T_(c).
 18. The method of claim 16, wherein the particle core is selected from the group consisting of an elemental metal, a chelated metal, a metal complex, a metal oxide, a metal hydroxide, a metal alloy and combinations thereof.
 19. The method of claim 16, wherein the coating material comprises a plurality of coating layers.
 20. The method of claim 16, wherein the amount of the metallic powder particles in the emulsion breaking fluid ranges from about 0.01 to about 10,000 ppm. 